create snippets for use in emacs-yasnippet

plus more cleanup of main tidal file, and updated readme

snippets/b1drum2

@@ -0,0 +1,14 @@
+# -*- mode: snippet -*-
+# name: b1drum2
+# group: battery123
+# key: b1drum2
+# expand-env: (yas-indent-line 'fixed)
+# --
+-- @b1drum2
+d'drum $ cf $
+  stack [
+    s "peri*2", -- (-1) remove
+    -- every' 8 8 (density 1.5) $ -- (2)
+    -- every 2 (density 3) $ -- (1)
+    sound "~ psr:1"
+    ]